I was finally able to find my 4.7 CD and installed it on a test machine, but the File | Save As menu item is still greyed out. What version of IE are you using? I'm using 5.0something. I know that changes had to be made during Procomm's development whenever a new version of IE came out, so the problem I am probably having is due to Procomm not being able to interface with a newer version of IE than was aroun when Procomm was developed. So, I can't quite test the problem you are seeing.
However, I was able to test this using an IE window instead of Procomm's browser and was able to send the Alt-S using a script, so it appears to be a problem due to the integration of IE into Procomm. Here are a couple other things to try to see if you can work around the problem. First, if you bring up the Save Picture dialog manually by selecting the File | Save As menu item in Procomm, does the dialog appear to have focus? If not, we could use a winactivate command to set focus to the dialog. If the dialog does have focus, are you able to manually press Alt-S to save the picture?